One of the most timely problems with the dressing of fur skins is the partial or complete replacement to be found for auxiliary agents, which put a high load on industrial sewage waters. With regard to dressing fur skins, in particular, basic aluminum tanning agents, in combination with other tanning and dressing agents, if desired, are normally used. However, resulting properties of the dressed fur skins, such as water resistance and shrinkage temperature, are frequently not satisfactory.